Supplementary Material for: Outcomes of En Bloc Kidney Transplants from Small Deceased Pediatric Donors to Adult Recipients: A Single-Center Experience

Introduction
The shortage of donor grafts for kidney transplantation remains a critical challenge. En bloc kidney transplantation (EBKT) from small deceased pediatric donors can potentially expand the donor pool. This study aimed to investigate the safety of pediatric-donor EBKT in adults compared with the standard deceased kidney transplantation (SDKT).
Methods
This retrospective study was performed to compare outcomes after pediatric-donor EBKT (n = 17; donor weight, 9.8  4.0 kg) and SDKT (n = 72; donor weight, 79.6  18.4 kg) in adult recipients at our center. Outcomes of EBKT from donors weighing 10 kg were compared with those from donors weighing ≥10 kg. The primary outcome was death-censored graft survival. Secondary outcomes included patient survival, serum creatinine, and the incidence of postoperative complications.
Results
The death-censored graft survival rates at 1, 5, and 10 years were 0.86 ± 0.09, 0.86 ± 0.09, and 0.86 ± 0.09, respectively, for pediatric-donor EBKTs, and 0.84 ± 0.05, 0.76 ± 0.07, and 0.64 ± 0.13, respectively, for SDKTs (P > 0.05). The patient survival rates at 1, 5, and 10 years were 0.93 ± 0.06, 0.67 ± 0.16, and 0.24 ± 0.20, respectively, for pediatric-donor EBKTs, and 0.86 ± 0.04, 0.60 ± 0.08, and 0.42 ± 0.10, respectively, for SDKTs (P > 0.05). No significant differences were observed between pediatric-donor EBKT and SDKT groups in postoperative complications (P > 0.05). Subgroup analysis of pediatric-donor EBKT by donor body weight revealed no significant differences (P > 0.05) in long-term graft and patient survival.
Conclusion
Pediatric-donor EBKT in adults is a safe approach, with outcomes comparable to those of SDKT in our study. Moreover, EBKT from donors weighing <10 kg demonstrated comparable long-term graft and patient survival to that from donors weighing ≥10 kg. Considering the small sample size and the increased mortality observed over time, further research involving larger cohorts is necessary to validate these findings and to refine criteria for optimal recipient selection.